# Copyright 2020-2025 The HuggingFace Team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# /// script
# dependencies = [
#     "trl[vllm]",
# ]
# ///

from dataclasses import dataclass, field

from datasets import load_dataset
from transformers import HfArgumentParser
from vllm import LLM, SamplingParams

from trl.experimental.judges import HfPairwiseJudge, OpenAIPairwiseJudge


"""
Examples:

python examples/scripts/evals/judge_tldr.py --model_name_or_path vwxyzjn/rloo_tldr --num_examples 1000
Model win rate: 31.40%

python examples/scripts/evals/judge_tldr.py --model_name_or_path vwxyzjn/rloo_tldr --judge_model gpt-3.5-turbo-0125 --num_examples 1000
Model win rate: 51.60%

python examples/scripts/evals/judge_tldr.py --model_name_or_path vwxyzjn/rloo_tldr --judge_model gpt-4o-mini --num_examples 1000
Model win rate: 51.20%

python examples/scripts/evals/judge_tldr.py --model_name_or_path vwxyzjn/ppo_tldr --num_examples 1000
Model win rate: 46.30%

python examples/scripts/evals/judge_tldr.py --model_name_or_path vwxyzjn/ppo_tldr --judge_model gpt-3.5-turbo-0125 --num_examples 1000
Model win rate: 52.50%

python examples/scripts/evals/judge_tldr.py --model_name_or_path vwxyzjn/ppo_tldr --judge_model gpt-4o-mini --num_examples 1000
Model win rate: 63.00%
"""


@dataclass
class ScriptArguments:
    r"""
    Arguments for the script.

    Args:
        model_name_or_path (`str`):
            Model name or path to the model to evaluate.
        judge_model (`str`, *optional*, defaults to `"meta-llama/Meta-Llama-3-70B-Instruct"`):
            Model name or path to the model to use as a judge. E.g., 'gpt-3.5-turbo-0125' or
            'meta-llama/Meta-Llama-3-70B-Instruct'.
        num_examples (`int`, *optional*):
            Number of examples to evaluate.
    """

    model_name_or_path: str = field(metadata={"help": "Model name or path to the model to evaluate."})
    judge_model: str = field(
        default="meta-llama/Meta-Llama-3-70B-Instruct",
        metadata={
            "help": "Model name or path to the model to use as a judge. E.g., 'gpt-3.5-turbo-0125' or "
            "'meta-llama/Meta-Llama-3-70B-Instruct'."
        },
    )
    num_examples: int | None = field(default=None, metadata={"help": "Number of examples to evaluate."})


if __name__ == "__main__":
    # Parse the arguments
    parser = HfArgumentParser(ScriptArguments)
    script_args = parser.parse_args_into_dataclasses()[0]

    # Load the dataset
    dataset = load_dataset("trl-lib/tldr", split="validation")
    if script_args.num_examples is not None:
        dataset = dataset.select(range(script_args.num_examples))

    # Extract the prompts and reference completions
    prompts = dataset["prompt"]
    reference_completions = dataset["completion"]

    # Generate the model completions
    sampling_params = SamplingParams(temperature=0.0, top_p=0.95, max_tokens=200)  # very generous max token length
    llm = LLM(model=script_args.model_name_or_path, tensor_parallel_size=1)
    outputs = llm.generate(prompts, sampling_params)
    model_completions = [output.outputs[0].text.strip() for output in outputs]

    # Judge the outputs
    if "gpt" in script_args.judge_model:
        judge = OpenAIPairwiseJudge(script_args.judge_model)
    else:
        judge = HfPairwiseJudge(script_args.judge_model)

    completions = [[c0, c1] for c0, c1 in zip(reference_completions, model_completions, strict=True)]
    best_idxs = judge.judge(prompts, completions)
    model_win_rate = best_idxs.count(1) / len(best_idxs)
    print(f"Model win rate: {model_win_rate * 100:.2f}%")
